This invention pertains generally to a guidewire assembly which is particularly useful with dilatation catheters in valvuloplasty procedures.
Balloon dilatation catheters have come into widespread use for treating stenotic lesions in coronary and peripheral arteries. These catheters are typically advanced through a patient's vasculature over a guidewire assembly until the inflatable balloon on the distal extremity of the catheter traverses the stenosis to be dilated. The balloon is then inflated to dilate the opening or lumen.
Stenoses can also occur in heart valves, particularly the aortic and mitral valves. While in the past valve replacement might be the preferred treatment, particularly with severe stenoses, more frequently the valvular stenosis has been successfully treated with dilatation balloon catheters in a procedure known as valvuloplasty or commissurotomy. However, in these procedures, the inflatable balloons are much larger than those used in typical coronary and peripheral dilatations. Moreover, a plurality of balloons are frequently disposed across the stenotic valves and inflated simultaneously to effectively dilate the heart valves.
In order to advance the relatively large diameter balloon catheters across the aortic or mitral valves, a relatively stiff guidewire must be first passed through the valve. However, once the relatively stiff guidewire has passed through the valve, care must be exercised in order to ensure that the distal tip of the guidewire does not traumatically engage the inner lining of the heart.
What has been needed and heretofore unavailable is a guidewire assembly for valvuloplasty procedure, which can be relatively stiff to facilitate passage through a mitral or aortic valve but which can assume a flexible, non-traumatic form once advanced through the valve in order to avoid injury to the interior of the heart. The present invention satisfies that need.